jQuery Grid Plugin - jqGrid

Sorry for another post.  jqgrid is working very well, you only hear the problems.  

How to save the row data if editRow of new row has error from server???   This is - adding - a new row with inline editing.  

When an error from server, such as missing field, the user entries are lost for all the row when server reply 'missing field'.  

editrules: { required: true } prevents this for text fields.  But, number fields, zero fools jqgrid to think user entered data.  (Zero displayed in cell from formatter: 'integer'   Maybe there is better way so number field is blank and client catches this?  Even so, better to know how to handle server-side error in case for future).

So, the server finds zero, and return error.  (Simple check on client not OK for this requirements).

When error returned to grid, how keep the cell entries up to this point in the row?   All row entries are gone and the user must start over.